From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8EBFFC43214 for ; Wed, 18 Aug 2021 08:57:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 740506109E for ; Wed, 18 Aug 2021 08:57:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230496AbhHRI6P (ORCPT ); Wed, 18 Aug 2021 04:58:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230331AbhHRI6N (ORCPT ); Wed, 18 Aug 2021 04:58:13 -0400 Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 617D7C0613CF for ; Wed, 18 Aug 2021 01:57:39 -0700 (PDT) Received: by mail-ed1-x535.google.com with SMTP id dj8so2015080edb.2 for ; Wed, 18 Aug 2021 01:57:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tessares-net.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=yyB09rflCzHIn1ju5X9fd70kpkBZLkV0jkVgx5Jum1M=; b=eUXyKdJAzmmk9t9EBWMwn5DQQ/3lULWEUIXsJT6jM89cXNHXUK+6MhzdMrncDYiKdE 3LtdGmfp1B7S/lU3UCxJLF9bM2hjDv350E1zN4Xsbsmo/pTOkY9ErxHacO2nm7Sd3mRm yh/CK53CmSUPNd1H6VYQechEs9zkG9LFweVaADOOfpNXJ2osI0aUZKBPiLFqmlwViXJv ha5Hk+7eKJ3jOiJYHascMT/otfIdpe320Z7iQ3AzXwXi+/BzxXKk9Qn73lvz/vD5Cyfo 2IhGDb9ZmPpLtOXYH4I6CLMuZi2EfYiqcXZvuNuEgUL78PluLKvPncpOhR6zSmPnXBdB quHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=yyB09rflCzHIn1ju5X9fd70kpkBZLkV0jkVgx5Jum1M=; b=TN3BJVj8MBnJJrZkpJrmJt2UDnZHA7YLAqEgZTkOusov6+s+YdAzaxCqzGz/MDbu+5 MbJUdpV4NaGiGUOIg+S0TI1UJp7oxGNWdIs6NQgNDaDEwkGkWqbriHlHgm7/kNka0n8Z NnIZDjAyteqjLQjm+giqEzJRwi3OHbnEHRYQWLxelBPfl2ZxfxlpPRGe0qmP8Hxv8OT/ EjZxB0KkTesOoL2c+qOthfjB90PRDsWn6CssLKCVza676OXKiB6YWRmbRfQW5cFlL3U/ NtcNGXZ0DLyVrXoFouGhpyvrRLB7WHvd8N06oQ8PV/fjR/CHzkbCu6KWexUTvpyvThpD NcZQ== X-Gm-Message-State: AOAM5301apkbKHd5xlTUi28byDoDMKpw4K5fDk2RRDaeqjJ4Vy19iJGD InPi7w8lwwDzI9IVpbIVWoU1pA== X-Google-Smtp-Source: ABdhPJzGR88Pk3GJEFXwZCriKTFugvn/HeIUrvcrkEfL+IGeE0KfFWsxaBzduCrnXLd9v8ytkPDFXw== X-Received: by 2002:aa7:c894:: with SMTP id p20mr8907066eds.42.1629277058064; Wed, 18 Aug 2021 01:57:38 -0700 (PDT) Received: from tsr-lap-08.nix.tessares.net ([213.211.156.192]) by smtp.gmail.com with ESMTPSA id n10sm1759880ejk.86.2021.08.18.01.57.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Aug 2021 01:57:37 -0700 (PDT) Subject: Re: [syzbot] KFENCE: use-after-free in kvm_fastop_exception To: Pavel Skripkin , syzbot , davem@davemloft.net, johan.hedberg@gmail.com, kuba@kernel.org, linux-bluetooth@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, luiz.dentz@gmail.com, marcel@holtmann.org, mathew.j.martineau@linux.intel.com, netdev@vger.kernel.org, pabeni@redhat.com, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk References: <00000000000012030e05c9c8bc85@google.com> <58cef9e0-69de-efdb-4035-7c1ed3d23132@tessares.net> <6736a510-20a1-9fb5-caf4-86334cabbbb6@gmail.com> <32aeb66e-d4f0-26b5-a140-4477bb87067f@tessares.net> <3a8dd8db-61d6-603e-b270-5faf1be02c6b@gmail.com> From: Matthieu Baerts Message-ID: Date: Wed, 18 Aug 2021 10:57:36 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <3a8dd8db-61d6-603e-b270-5faf1be02c6b@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/08/2021 10:55, Pavel Skripkin wrote: > On 8/18/21 11:21 AM, Matthieu Baerts wrote: >> Hi Pavel, >> > [snip] >>>> >>>> I'm pretty sure the commit c4512c63b119 ("mptcp: fix 'masking a bool' >>>> warning") doesn't introduce the reported bug. This minor fix is >>>> specific >>>> to MPTCP which doesn't seem to be used here. >>>> >>>> I'm not sure how I can tell syzbot this is a false positive. >>>> >>> >>> >>> looks like it's fs/namei bug. Similar reports: >>> >>> https://syzkaller.appspot.com/bug?id=517fa734b92b7db404c409b924cf5c997640e324 >>> >>> >>> >>> https://syzkaller.appspot.com/bug?id=484483daf3652b40dae18531923aa9175d392a4d >>> >> >> Thank you for having checked! >> Should we mark them as "#syz dup" if you think they have the same root >> cause? >> > > I think, yes, but I want to receive feedback from fs people about this > bug. There were huge updates last month, and, maybe, I am missing some > details. Alloc/free calltrace is the same, but anyway, I want some > confirmation to not close different bugs by mistake :) > > If these bugs really have same root case I will close them manually > after fix posted. Thank you for the explanation. Sounds good to me! Cheers, Matt -- Tessares | Belgium | Hybrid Access Solutions www.tessares.net